It is well known that microprocessors and other electronic devices in computer systems generate heat as a result of electrical activity taking place within the electronic devices. The heat must be managed so that it does not damage such devices or negatively affect their performance. Accordingly, many microprocessors are associated with a liquid cooling loop in which is circulated a coolant capable of transferring heat away from the microprocessor, thereby cooling the microprocessor to an acceptable temperature.
Because of its excellent thermal properties, water is widely used as a major component of coolants in computer cooling systems. An anti-freezing agent (antifreeze) is typically added to the water in order to provide freeze protection for the coolant. Potassium formate is one of the best anti-freezing agents currently available, but potassium formate is also highly corrosive to silicon, copper, aluminum, silver, and other metallic and non-metallic substances that are likely to be present in the cooling system. Corrosion by-products within the cooling system can interfere with heat transfer, which may subsequently cause overheating and failure of the microprocessor or other electronic device.
The general practice for reducing such corrosion risk is to add corrosion inhibitors to the coolant. But conventional corrosion inhibitors do not provide adequate corrosion protection against the pitting, crevice, and deposit attack corrosion phenomena that are seen with aluminum, silicon and silicon-based materials, and various light metal alloys. Furthermore, corrosion inhibition in microelectronics poses challenges and is subject to sensitivities not seen in other applications (such as, for example, automotive cooling systems) because microelectronic cooling systems use a relatively small amount of coolant for a relatively large internal surface area. The large ratio of surface area to coolant volume (the A/V ratio) that results demands that the make-up of corrosion inhibitors in the microelectronics coolant be chosen more carefully and effectively than in other cooling situations because such inhibitors tend to be much more quickly consumed. Furthermore, any amount of corrosion that does occur, however minor and whether due to poor selection of corrosion inhibitors or some other reason, can produce a serious acceleration in the corrosion rate—far more serious than what would typically be encountered in cooling situations outside of the microelectronics arena. Accordingly, there exists a need for a coolant capable of providing high levels of corrosion protection to silicon, aluminum, aluminum alloys, copper, and other components of microprocessor cooling systems.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the discussion of embodiments of the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements.
The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “comprise,” “include,” “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical or non-electrical manner.